1. Field of the Invention
This invention relates to on-ground beam forming to enhance gain to a desired user.
2. Background
Various satellite communication systems have been developed over the years. One early system architecture is referred to as Time Division Multiple Access (TDMA) and is characterized by assignment of time slots in a communication channel to each of a plurality of terminals, and with communication with the terminals taking place in the specifically assigned time slots. An improved system architecture is referred to as Code Division Multiple Access (CDMA). CDMA based communication systems generally provide greater bandwidth efficiency than do TDMA based communication systems.
In general, signal strength is a critical factor in establishing a communication link with good quality of service (QoS). In the case of satellite communications with multiple subscribers, the signal strength provided to subscribers' wireless communication devices (WCDs) by the satellite and by the WCDs to the satellite is limited. In addition, satellite coverage area is divided into plural beams, which are of limited geographical area.
If it can be determined which beam coincides with a WCD's physical location, the communication can be established within that beam. For the purposes of this description, the beam to which the WCD is assigned is the primary beam. Other WCDs are assigned beams as primary beams, so that this description of the primary beam is dependent on the location of a particular WCD with which an air link is established. In other words, the reference to a “primary beam” is dependent on which WCD is being described in connection with the communication and is dependent on the physical location of that WCD.
The backhaul is transmitted and received through one or more gateways. The backhaul corresponds to communication link between the satellite and the gateways, with the degree of processing performed by the satellite a matter of the particular design of the satellite.